Turnera ulmifolia L. (Turneraceae): preliminary study of its antioxidant activity

Turnera ulmifolia L. is used in Brazilian folk medicine as an anti-inflammatory. Since this activity may be correlated with the presence of antioxidant compounds, a leaf extract was evaluated for its radical scavenging capacity (RSC). The in vitro RSC of a 50% hydroethanolic (HE) extract was evaluated by beta-carotene/linoleic acid coupled oxidation system for the inhibition of oxidation and the lipid peroxidation inhibition in rat brain homogenates, using thiobarbituric acid reactive substances (TBARS) and chemiluminescence (CL). Results indicated, through peroxidation suppression, that this extract exhibited greater antioxidative activity (77.4% +/- 10%) than alpha-tocopherol (58.4% +/- 3.7%). TBARS and CL inhibition was concentration-dependent and Q(1/2) values were 8.2 and 6.0 microg/mL for TBARS and CL, respectively. For alpha-tocopherol these values were 7.1 microg/mL (TBARS) and 9.8 microg/mL (CL). Phenolic compounds may be responsible for this antioxidant capacity.

Efficacy and Safety of Sclerotherapy Using Polidocanol Foam: A Controlled Clinical Trial

OBJECTIVE

To assess the efficacy and safety of sclerotherapy performed with polidocanol foam compared to liquid polidocanol.

METHODS

Controlled clinical trial with 1 year follow up in which each patient acted as his/her own control. A total of 75 patients (six men and 69 women) with reticular or postoperative varices were enrolled and sclerotherapy was performed with liquid and with foam (Tessari method) using the same quantity of sclerosant for homogeneous varicose regions, to a total of 150 procedures. The sclerosant concentration was adjusted according to the vein diameter as assess by ultrasonography. The foam group was given 50% lower concentrations of sclerosant than liquid sclerosant group. Clinical assessment (pain, inflammation, pigmentation) and ultrasound examination (diameter of the lumen and length of sclerosed vein) were carried out at 15, 30, 90, and 365 days.

RESULTS

Foam allowed complete sclerosis at 90 days in 94.4% of patients compared with 53% for liquid (p<.001) and also allowed a more extensive venous sclerosis (10.1cm compared with 7.2 cm; p<.001). Pain, signs of inflammation, and pigmentation appeared more often with foam sclerosis, with significant difference. The degree of satisfaction was similar for both techniques.

CONCLUSIONS

Efficacy of venous sclerosis with foam seems to be greater than with liquid although there is a higher risk of minor secondary effects.

Phosphorylation and subcellular localization of transmissible gastroenteritis virus nucleocapsid protein in infected cells

The nucleocapsid (N) protein is the only phosphorylated structural protein of the coronavirus Transmissible gastroenteritis virus (TGEV). The phosphorylation state and intracellular distribution of TGEV N protein in infected cells were characterized by a combination of techniques including: (i) subcellular fractionation and analysis of tryptic peptides by two-dimensional nano-liquid chromatography, coupled to ion-trap mass spectrometry; (ii) tandem mass-spectrometry analysis of N protein resolved by SDS-PAGE; (iii) Western blotting using two specific antisera for phosphoserine-containing motifs; and (iv) confocal microscopy. A total of four N protein-derived phosphopeptides were detected in mitochondria–Golgi–endoplasmic reticulum–Golgi intermediate compartment (ERGIC)-enriched fractions, including N-protein phosphoserines 9, 156, 254 and 256. Confocal microscopy showed that the N protein found in mitochondria–Golgi–ERGIC fractions localized within the Golgi–ERGIC compartments and not with mitochondria. Phosphorylated N protein was also present in purified virions, containing at least phosphoserines 156 and 256. Coronavirus N proteins showed a conserved pattern of secondary structural elements, including six β-strands and four α-helices. Whilst serine 9 was present in a non-conserved domain, serines 156, 254 and 256 were localized close to highly conserved secondary structural elements within the central domain of coronavirus N proteins. Serine 156 was highly conserved, whereas no clear homologous sites were found for serines 254 and 256 for other coronavirus N proteins.

Receptors, rafts, and microvesicles in thrombosis and inflammation

Hemostasis at sites of blood vessel injury and its pathologic counterpart, thrombosis, involve a complex interplay between several blood elements: soluble proteins of the blood coagulation system, blood cells (most prominently platelets) and cell fragments, and elements of the vessel wall (endothelial cells and, at sites of injury, the exposed matrix and deeper cellular components). In this review, we focus on ways in which specialized membrane microdomains known as lipid rafts are involved in various phases of hemostasis and thrombosis.

Identification of Proteins Expressing Differences among Isolates of Meloidogyne spp. (Nematoda: Meloidogynidae) by Nano-Liquid Chromatography Coupled to Ion-Trap Mass Spectrometry

Total protein variation (up to ninety-five different positions) was revealed by two-dimensional electrophoresis (2-DE) in 18 isolates from populations of M. arenaria (6 isolates), M. incognita (10), M. javanica (1) plus an unclassified isolate in a previously reported study. Isolates of M. arenaria, M. javanica, Meloidogyne sp., and M. incognita formed two separate groups defined on the basis of two sets of protein positions that could be considered as diagnostic characters, but we could not identify these proteins by MALDI-TOF. To identify these marker positions, nano-liquid chromatography as peptides separation method was coupled to an ion-trap mass spectrometer for induced real-time fragmentation of eluted peptides. Group diagnostic proteins for M. incognita and M. arenaria were in-gel digested and on line analyzed by tandem mass spectrometry (LC-MS/MS). Six proteins out of seven selected spots were unambiguously identified by the analysis of the corresponding MS/MS (MS2) spectrum from parent ions fragmentation: Actin, Enolase, CG3752-PA protein similar to Aldehyde Dehydrogenase, HSP-60 and Translation initiation factor elF-4A. In M. incognita sample, de novo sequencing experiment of doubly charged ion at m/z=936.9 Da in spot 29 identified as enolase, reveals three residue substitutions (K to T, N to T, and D to E) when tentative sequence was compared with that of Anisakis simplex and Onchocerca volvulus enolase, thus three SNPs (single nucleotide polymorphisms) were also possibly identified.

Liver transplantation in infants weighing under 7 kilograms: management and outcome of PICU

Liver transplantation (LT) is an established treatment for children with acute and chronic liver failure. Some reports suggest that infants under the age of 1 yr and children weighing under 13 kg are high-risk groups associated with less satisfactory results. This report describes our experience during the pediatric intensive care unit stay of 16 infants weighing <7 kg who received LT. We reviewed the records of 16 infants with median age 7.4 months and median weight 5.8 kg, who received 18 liver allografts, nine whole and nine reduced. We also reviewed the use of adrenergic agonist agents, anti-infectious agents, antihypertensive agents, diuretics, immunosuppression protocol, sedation-analgesia agents, others agents (prostaglandin E(1), heparin and dipyridamole), diagnosis and management of rejection episodes, follow-up examination, nutrition and outcome. Mean peri-operative blood transfusions were 204 mL/kg, 188 mL/kg of plasma and 36 mL/kg of platelets; mean operative time was 5 h. Primary abdominal wound closure was possible in nine patients. Median initial intensive care unit stay was 18 days. Reasons for an initial stay of more than 18 days were retransplantation (1), gastrointestinal bleeding (2), paralytic ileus and atelectasis (2), septic shock (2), diaphragmatic paralysis, renal impairment and acute respiratory distress syndrome (2). Mean requirement for artificial ventilation was 168 h. Mean use of dobutamine, prostaglandin E(1) and dopamine was 3.3, 7.5 and 8.8 days, respectively. Parenteral nutrition was started at a mean of 48 h and oral food intake was started at a mean of 72 h. The most frequent complications were infection, atelectasis, gastrointestinal bleeding, acute renal failure and hepatic artery thrombosis. Four children required six re-explorations and two received retransplantation. Mean overall survival rate was 82% and graft survival was 72%. Weight alone (under 7 kg) should not be considered as a contraindication for LT. The survival rate of children post-LT is excellent regardless of graft type.

The use of reverse transcription-PCR for the diagnosis of X-linked chronic granulomatous disease

Chronic granulomatous disease (CGD) is an inherited disorder of the innate immune system characterized by a defective oxidative burst of phagocytes and subsequent impairment of their microbicidal activity. Mutations in one of the NADPH-oxidase components affect gene expression or function of this system, leading to the phenotype of CGD. Defects in gp91-phox lead to X-linked CGD, responsible for approximately 70% of CGD cases. Investigation of the highly heterogeneous genotype of CGD patients includes mutation analysis, Northern blot or Western blot assays according to the particular case. The aim of the present study was to use reverse transcription (RT)-PCR for the analysis of molecular defects responsible for X-linked CGD in eight Brazilian patients and to assess its potential for broader application to molecular screening in CGD. Total RNA was prepared from Epstein B virus-transformed B-lymphocytes and reverse transcribed using random hexamers. The resulting cDNA was PCR-amplified by specific and overlapping pairs of primers designed to amplify three regions of the gp91-phox gene: exons 1-5, 3-9, and 7-13. This strategy detected defective gp91-phox expression in seven patients. The RT-PCR results matched clinical history, biochemical data (nitroblue tetrazolium or superoxide release assay) and available mutation analysis in four cases. In three additional cases, RT-PCR results matched clinical history and biochemical data. In another case, RT-PCR was normal despite a clinical history compatible with CGD and defective respiratory burst. We conclude that this new application of RT-PCR analysis--a simple, economical and rapid method--was appropriate for screening molecular defects in 7 of 8 X-linked CGD patients.

Von Willebrand factor present in fibrillar collagen enhances platelet adhesion to collagen and collagen-induced platelet aggregation

We examined the basis of the differences observed between different collagen preparations in their ability to aggregate platelets and support their adhesion under flow. As in previous studies, we found fibrillar collagen to be 10-fold more potent than acid-soluble collagen in inducing platelet aggregation and found that acid-soluble collagen did not support the adhesion of washed platelets under flow. Further, platelets in whole blood adhered to surfaces coated with either fibrillar or acid-soluble collagen, but thrombi formed faster and grew larger on fibrillar collagen. As a possible basis for this difference, we found that fibrillar collagen, but not acid-soluble collagen, contains a substantial quantity of von Willebrand factor (VWF), as demonstrated by enzyme-linked immunosorbent assay and by the ability of fibrillar collagen to support the adhesion of VWF antibody-coated beads and to agglutinate GPIb-IX-V complex-expressing Chinese hamster ovary cells. Supporting a role for VWF in collagen-induced platelet aggregation, aggregation induced by acid-soluble collagen was greatly enhanced by added VWF. Further, platelet aggregation by fibrillar collagen was partially blocked by a GPIbalpha antibody that inhibits the GPIb-VWF interaction. Taken together, these results suggest that much of the difference in prothrombotic potency of different collagens is directly related to their differences in VWF content. This probably accounts for the different conclusions made regarding the relative importance of different direct and indirect collagen receptors in collagen-dependent platelet functions and further emphasizes the close synergistic roles of the GPIb-IX-V complex and the collagen receptors GPVI and alpha2beta1 in supporting platelet adhesion.

Prognostic significance of the p185 protein in colorectal cancer

The amplification and/or overexpression of the c-erbB-2/neu oncogene may play a role in tumor development and progression. The aim of this prospective study was to evaluate the prognostic value of p185 protein in colorectal cancer using immunohistochemical techniques. We analyzed 106 colorectal tumor tissue specimens from patients who had been operated on by the same surgeon and subjected to a median follow-up of 3 years. Thirty-three per cent of patients showed p185 overexpression related to an advanced stage of the disease. In patients with adenocarcinoma tumors of the colon without distant metastases, p185 detection was found to be of clinical prognostic relevance (p = 0.06).

Glycoprotein Ib-IX-mediated activation of integrin alpha(IIb)beta(3): effects of receptor clustering and von Willebrand factor adhesion

The interaction between the platelet glycoprotein (GP) Ib-IX complex and von Willebrand factor (VWF) initiates both hemostasis and pathological thrombosis. This interaction is not only the first adhesive event of platelets at sites of vessel injury, but also facilitates fibrinogen binding to alpha(IIb)beta(3), which subsequently results in platelet aggregation. Since it has been suggested that GP Ib-IX clustering may promote platelet activation, we investigated the effect of such clustering on both VWF-GP Ib-IX and fibrinogen-alpha(IIb)beta(3) bonds using optical tweezers. In our system, fusion of tandem repeats of FK506-binding protein (FKBP) to the cytoplasmic tail of the GP IX subunit of the GP Ib-IX complex allowed subsequent receptor clustering within the plasma membrane by the bivalent, cell-permeant small molecule ligand AP20187. We measured binding forces between polystyrene beads coated with either plasma-derived VWF or the VWF A1 domain and GP Ib-IX(FKBP)2, and those between fibrinogen-coated beads and alpha(IIb)beta(3) expressed on Chinese hamster ovary cells. The minimal detachment force between GP Ib-IX(FKBP)(2) and A1 or plasma-derived VWF doubled after AP20187 was added. The binding force between immobilized fibrinogen and alpha(IIb)beta(3) was not changed by the clustering agent; however, the strength of single fibrinogen-alpha(IIb)beta(3) bonds increased significantly after ligation of GP Ib-IX(FKBP)(2) by A1. These results demonstrate that GP Ib-IX clustering increases the overall strength of its interaction with VWF. Furthermore, signals from GP Ib-IX can activate alpha(IIb)beta(3), thereby increasing the strength of its interaction with fibrinogen.

Sulfatides inhibit platelet adhesion to von Willebrand factor in flowing blood

Sulfatides are sulfated glycosphingolipids present on cell surfaces that bind to adhesive proteins such as von Willebrand factor (VWF), P-selectin, laminin and thrombospondin. Previous studies have localized the sulfatide-binding site of VWF to amino acid residues Gln626-Val646 in the A1 domain. The A1 domain also contains the binding site for platelet glycoprotein Ib (GP Ib), a site that has been reported to be distinct from the sulfatide-binding site. In this study, we analyzed the interaction of sulfatides with VWF and its effect on GP Ib-mediated platelet adhesion under flow conditions. Recombinant VWF A1 domain (rVWF-A1) bound specifically and saturably to sulfatides (half-maximal concentration of approximately 12.5 microg mL(-1)), binding that was blocked by dextran sulfate (IC(50) approximately equal to 100 microg mL(-1)) but not by heparin at concentrations up to 100 U mL(-1). Furthermore, sulfatides (125 microg mL(-1)) prevented the adhesion of platelets or glycocalicin-coupled polystyrene beads to a rVWF-A1-coated surface under high shear stress. In addition, plasma VWF prebound to a sulfatide-coated surface failed to support subsequent platelet adhesion. These results provide firm evidence that sulfatides bind the VWF A1 domain at a site overlapping the GP Ib-binding site.

Portable pilot plant for evaluating marine biofouling growth and control in heat exchangers-condensers

Biofouling frequently involves a serious impediment to achieving optimum operating conditions in heat exchangers-condensers. The economic coat and energy losses associated with this phenomenon are significant and the environmental impact of biocides must satisfy stringent regulations. A portable pilot plant has been designed in order to carry out in-situ experimental study as biofilm is formed under thermal and hydrodynamically controlled conditions. The pilot plant has an automatic monitoring, control and data acquisition system, which automatically processes data from indirect measure of fouling in terms of increased fluid frictional and heat transfer resistances. A particular method is used and proposed for direct measuring and biofilm characterization. Once we know the actual film thickness, we can calculate the effective thermal conductivity of the layer by using the appropriate heat transfer equations.

Protein variability in Meloidogyne spp. (Nematoda:Meloidogynidae) revealed by two-dimensional gel electrophoresis and mass spectrometry

Total protein variation as revealed by two-dimensional electrophoresis (2D-E) was studied in 18 isolates from populations of Meloidogyne arenaria (six isolates), Meloidogyne incognita (10 isolates), and Meloidogyne javanica (one isolate) plus an unclassified isolate. Gels (80 x 60 x 0.75 mm) were silverstained and digitized in order to compare their protein patterns. Optical density and position of protein patterns were measured using statistical cluster analysis and computer-assisted image analysis software. Only those protein stains or positions that were clearly defined (i.e., without background) were considered. The number of positions in gels ranged from 86 to 203. Each of these positions had 95 clearly expressed proteins that were present in at least two replicates for each isolate. Spot position was considered a taxonomical character with two different states: presence (1) and absence (0). Accordingly, genetic distance was estimated among isolates and species, and a phylogenetic tree was constructed following the cladistic approach based on maximum parsimony analysis. Isolates of M. arenaria--M. javanica--Meloidogyne sp. and of M. incognita formed two separate monophyletic groups. Both groups were clearly defined on the basis of two sets of protein positions that can be considered as diagnostic characters. An attempt to identify these proteins by mass spectrometry was made. Group diagnostic proteins for M. incognita and M. arenaria (and for other proteins common to all isolates) were distinguished by protonated mass signals in the MALDI fingerprinting spectrum.

Fast screening method for the determination of angiotensin II receptor antagonists in human plasma by high-performance liquid chromatography with fluorimetric detection

A selective, accurate and precise high-performance liquid chromatographic assay coupled to fluorescence detection was developed for the detection of some angiotensin II receptor antagonists (ARA II): Losartan, Irbesartan, Valsartan, Candesartan cilexetil and its metabolite Candesartan MI. The analytes and the internal standard (bumetanide, a high-ceiling diuretic) were extracted from plasma under acidic conditions by means of solid-phase extraction using C8 cartridges. This procedure allowed recoveries close to 80% for all these drugs excluding Candesartan cilexetil (70%) which presented adsorption processes on glass and plastic walls. The analytes and potential interferences were separated on a reversed-phase column, muBondapak C18, at room temperature. A gradient elution mode was used to carry out the separation, the optimal mobile phase being composed of acetonitrile-5 mM acetate buffer, pH 4, at variable flow-rates (from 1.0 to 1.2 ml/min). Fluorescence detector was set at an excitation wavelength of 250 nm and an emission wavelength of 375 nm. Intra- and inter-day relative standard deviations for all the compounds were lower than 8% except for Losartan (12%) and the method assesses a quite good accuracy (percentage of relative error approximately 6% in most of the cases). The limit of quantitation for these compounds was 3 ng/ml for Candesartan cilexetil and M1, 16 ng/ml for Losartan and 50 ng/ml for Irbesartan and Valsartan, which allows their determination at expected plasma concentration levels. This assay method has been successfully applied to plasma samples obtained from hypertensive patients under clinical studies after oral administration of a therapeutic dose of some of these ARA II compounds.

Transmission of trans effects in dinuclear complexes

The substitution of a terminal hydride ligand in the complexes [Ir(2)(mu-H)(mu-Pz)(2)H(3)(L)P(i)Pr(3))(2)] (L = NCCH(3) (1) or pyrazole (3)) by chloride provokes a significant change in the lability of the L ligand, despite the fact that the substituted hydride and the L ligand lie in opposite extremes of the diiridium(III) complexes. Detailed structural studies of complex 3 and its chloro-trihydride analogue [Ir(2)(mu-H)(mu-Pz)(2)H(2)Cl(HPz)(P(i)Pr(3))(2)] (4) have shown that this behavior is a consequence of the transmission of ligand trans effects from one extreme of the molecule to the other, with the participation of the bridging hydride. Extended Hückel calculations on model diiridium complexes have suggested that such trans effect transmissions are due to the formation of molecular orbitals of sigma symmetry extended along the backbones of the complexes. This is also an expected feature for metal-metal bonded complexes. The feasibility of the transmission of ligand trans effects and trans influences through metal-metal bonds and its relevance to the understanding of both the reactivity and structures of metal-metal bonded dinuclear compounds have been substantiated through structural studies and selected reactions of the diiridium(II) complexes [Ir(2)(mu-1,8-(NH)(2)naphth)I(CH(3))(CO)(2)(P(i)Pr(3))(2)] (isomers 6 and 7) and their cationic derivatives [Ir(2)(mu-1,8-(NH)(2)naphth)(CH(3))(CO)(2)(P(i)Pr(3))(2)](CF(3)SO(3)) (isomers 8 and 9).

Role of Kozak sequence polymorphism of platelet glycoprotein Ibalpha as a risk factor for coronary artery disease and catheter interventions

OBJECTIVES

We sought to determine the role of the -5T/C polymorphism of the platelet glycoprotein (GP) Ibalpha as a potential risk factor for coronary artery disease (CAD) and adverse events complicating a coronary catheter intervention.

BACKGROUND

The platelet GP Ib-IX-V receptor complex plays a crucial role in arterial thrombus formation. The -5T/C polymorphism of GP Ibalpha is associated with increased receptor density.

METHODS

We genotyped 1,000 patients with angiographically confirmed CAD, as well as 1,000 age- and gender-matched control subjects, for this polymorphism by polymerase chain reaction/restriction fragment length polymorphism. Among the patients with CAD, 269 underwent percutaneous transluminal coronary angioplasty (PTCA), 103 underwent directional coronary atherectomy and 278 underwent stenting. This intervention group was followed for a 30-day composite end point of target vessel revascularization, myocardial infarction or death.

RESULTS

Carriers of the -5C allele were significantly over-represented in the group of patients developing acute coronary syndromes (relative risk [RR] 1.43, 95% confidence interval [CI] 1.05 to 1.95, p = 0.02). The -5C allele furthermore predicted an increased risk for developing complications after PTCA (RR 3.75, 95% CI 1.15 to 12.27, p = 0.029).

CONCLUSIONS

The -5C allele of the GP Ibalpha Kozak polymorphism may represent a risk factor in clinical conditions in which thrombosis plays an important role, such as in acute coronary syndromes and in complications after PTCA.

Synthesis of paramagnetic tetranuclear rhodium and iridium complexes with the 2,6-pyridinedithiolate ligand. Redox-induced degradation to diamagnetic triiridium compounds

The tetranuclear complexes [M4(mu-PyS2)2(diolefin)4] [PyS2 = 2,6-pyridinedithiolate; M = Rh, diolefin = cod (1,5-cyclooctadiene) (1), tfbb (tetrafluorobenzo[5,6]bicyclo[2.2.2]octa-2,5,7-triene) (2); M = Ir, diolefin = cod (3), tfbb (4)] exhibit two one-electron oxidations at a platinum disk electrode in dichloromethane at potentials accessible by chemical reagents. The rhodium tetranuclear complexes were selectively oxidized to the monocationic complexes [Rh4(mu-PyS2)2(diolefin)4](+) (1(+), 2(+)) by mild one-electron oxidants such as [Cp2Fe](+) or [N(C6H4Br-4)3](+) and isolated as the PF6(-), BF4(-), and ClO4(-) salts. Silver salts behave as noninnocent one-electron oxidants for the reactions with the rhodium complexes 1 and 2 since they give sparingly soluble coordination polymers. The complex [Ir4(mu-PyS2)2(cod)4](+) (3(+)) was obtained as the tetrafluoroborate salt by reaction of 3 with 1 molar equiv of AgBF4, but the related complex 4(+) could not be isolated from the chemical oxidation of [Ir4(mu-PyS2)2(tfbb)4] (4) with AgBF4. Oxidation of 3 and 4 with 2 molar equiv of common silver salts resulted in the fragmentation of the complexes to give the diamagnetic triiridium cations [Ir3(mu-PyS2)2(diolefin)3](+). The molecular structure of [Ir3(mu-PyS2)2(cod)3]BF4, determined by X-ray diffraction methods, showed the three metal atoms within an angular arrangement. Both 2,6-pyridinedithiolate tridentate ligands bridge two metal-metal bonded d(7) centers in pseudo octahedral environments and one d(8) square-planar iridium center. An interpretation of the EPR spectra of the 63-electron mixed-valence paramagnetic tetranuclear complexes suggests that the unpaired electron is delocalized over two of the metal atoms in the complexes 1(+)-3(+).

Cleavage of the human respiratory syncytial virus fusion protein at two distinct sites is required for activation of membrane fusion

Preparations of purified full-length fusion (F) protein of human respiratory syncytial virus (HRSV) expressed in recombinant vaccinia-F infected cells, or of an anchorless mutant (F(TM(-))) lacking the C-terminal 50 amino acids secreted from vaccinia-F(TM(-))-infected cells contain a minor polypeptide that is an intermediate product of proteolytic processing of the F protein precursor F0. N-terminal sequencing of the intermediate demonstrated that it is generated by cleavage at a furin-motif, residues 106-109 of the F sequence. By contrast, the F1 N terminus derives from cleavage at residue 137 of F0 which is also C-terminal to a furin recognition site at residues 131-136. Site-directed mutagenesis indicates that processing of F0 protein involves independent cleavage at both sites. Both cleavages are required for the F protein to be active in membrane fusion as judged by syncytia formation, and they allow changes in F structure from cone- to lollipop-shaped spikes and the formation of rosettes by anchorless F.

Synthesis and insertion reactions of the cyclometalated palladium-alkyl complexes Pd(CH(2)CMe(2)-o-C(6)H(4))L(2). Observation of a pentacoordinated intermediate in the insertion of SO(2)

Palladacycles of the type 2, have been synthesized by treatment of the corresponding chloroalkylcomplexes Pd(CH(2)CMe(2)C(6)H(5))ClL(2) (L(2) = (PMe(3))(2), 2a, or 1,5-cyclooctadiene (cod), 2b) with suitable bases, or by simple ligand exchange reactions from the cyclooctadiene derivative 2b. The metallacycles 2 react with activated alkynes and with sulfur dioxide, giving rise to different insertion products.

Surgical and physical stress increases circulating blood dendritic cell counts independently of monocyte counts

Dendritic cells (DCs) are specialized antigen-presenting cells that have the unique ability to initiate a primary immune response. The effect of physiologic stress on circulating blood DCs has thus far not been studied. In this study, we applied a recently developed method of counting blood DCs to test the hypothesis that significant stress to the body such as surgery and exercise might induce measurable changes in the DC numbers, subsets, phenotype, and function. Twenty-six patients scheduled for elective laparoscopic cholecystectomy, 4 for elective hysterectomy, 56 controls, and 5 volunteers who underwent a stress exercise test were enrolled in the study. Absolute DC counts increased acutely (71.7% +/- 11% [SEM], P =.0001) in response to the stress of surgery and dropped below preoperative levels (-25% +/- 14% [SEM], P =.05) on days 2-3. The perioperative DC subset balance remained constant. Interestingly, DC counts changed independently of monocyte counts. Exercise also induced a rise in DC counts but coincidentally with monocyte counts. Surprisingly, no phenotypic or functional activation of DCs was seen in either stress situations in vivo. DCs are rapidly mobilized into the circulation in response to surgical and exercise stress, which may serve to prepare the host's immune defenses against trauma. The independent regulation of the DC and monocyte counts reinforces the distinction between these 2 cell populations.

Expression of the amino-terminal domain of platelet glycoprotein Ib alpha: exploitation of a calmodulin tag for determination of its functional activity

Platelet glycoprotein (GP) Ibalpha is a component of the GPIb-IX receptor complex, which is involved in multiple physiological and pathological processes, including platelet adhesion at sites of vascular injury, thrombin binding, Bernard-Soulier syndrome, platelet-type von Willebrand disease, and immune-mediated thrombocytopenias. The amino-terminal domain of approximately 300 residues of GPIbalpha mediates both normal biological function (by providing the sites for direct ligand interaction) and aberrant function (through amino acid substitutions). To investigate the molecular interactions mediated by this region of GPIbalpha, we have developed a recombinant baculovirus to facilitate its expression as a calmodulin fusion protein from insect cells. By employing the calmodulin tag, the fusion protein could be obtained at >90% purity after a single isolation step at yields of 8 mg/L of insect cell medium (purified fusion protein). The recombinant GPIbalpha fragment was shown to be posttranslationally sulfated and glycosylated, although its glycosylation differed from that of the equivalent GPIbalpha fragment isolated from human platelets. The differential glycosylation, however, did not affect the function of the recombinant GPIbalpha fragment in either von Willebrand factor (vWf) or thrombin binding as these were both found to be identical to those of the same-length GPIbalpha fragment derived from human platelets. The calmodulin tag was also exploited in the development of assays to measure directly vWf and thrombin binding, since it did not interfere with either, demonstrating the feasibility for the use of this soluble receptor fusion protein in detailed biophysical assays to investigate the molecular mode of binding of platelet glycoprotein Ibalpha to these ligands.

A synthetic malaria vaccine elicits a potent CD8(+) and CD4(+) T lymphocyte immune response in humans. Implications for vaccination strategies

We report the first synthetic peptide vaccine eliciting strong CD8(+) and CD4(+) T lymphocyte responses in humans. The vaccine, representing the C-terminal region of the circumsporozoite protein of Plasmodium falciparum (amino acids 282-383) was well tolerated and strong sporozoite-specific antibodies were elicited. In addition, robust lymphocyte proliferation responses were equally elicited with concomitant in vitro production of IFN-gamma, crucial in the elimination of the parasite. Most importantly, we also observed the development of CD8(+) T lymphocyte responses decisive in the immunity to malaria. The latter finding opens new, possibly safer, avenues for vaccination strategies when a CD8(+) T cell response is needed.

Platelet glycoprotein Ibalpha Kozak polymorphism is associated with an increased risk of ischemic stroke

Platelets are pivotal to the process of arterial thrombosis resulting in ischemic stroke. Occlusive thrombosis is initiated by the interaction of von Willebrand factor (vWf) and platelet glycoprotein (GP) Ibalpha. Three polymorphisms have been described in GP Ibalpha (Kozak T/C polymorphism, variable number of tandem repeats [VNTR], and the human platelet antigen 2a [HPA-2a] [Thr] or HPA-2b [Met] at position 145), each of which may enhance the vWf and GP Ibalpha interaction. This study investigated whether these polymorphisms are candidate genes for first-ever ischemic stroke. A hospital-based case-control study was conducted of 219 cases of first-ever ischemic stroke and 205 community controls randomly selected from the electoral roll and stratified by age, sex, and postal code. The subtypes of stroke were classified, the prevalence of conventional risk factors was recorded, and blood was collected to perform genotyping analysis for Kozak C or T alleles, VNTR, and HPA-2a/b. It was found that the Kozak T/C genotype was over-represented in the stroke group (32.2%) compared with controls (22.8%) (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.03-2.54; P <.03), and the association was still present even after adjusting for conventional risk factors. There was a trend in the increased prevalence of HPA-2a/b in stroke patients (15%) compared with controls (9.9%) (adjusted OR, 1.8; 95% CI, 0.94-3.4; P =.07). No associations were seen with the VNTR polymorphism or with any of the polymorphisms with stroke subtype. It was concluded that the Kozak T/C polymorphism, which is associated with an increase in platelet GP Ibalpha surface expression, is an independent risk factor for first-ever ischemic stroke.